//KY74 字符串排序
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<iostream>
using namespace std;
bool cmp1(char a,char b)
{
    return a<b;
}
int main()
{
    char arr[20];
    memset(arr,'\0',20*sizeof(char));
    while(scanf("%s",&arr)!=EOF)
    {
        int len=strlen(arr);
        sort(arr,arr+len,cmp1);
        printf("%s\n",arr);
        memset(arr,'\0',20*sizeof(char));
    }
    return 0;
}